When you ask questions about using your detectors like how good is the pinpoint mode, etc. it would help if you include which of your detectors you are referring to. i am going to assume you are asking about the Whites Treasure Master which is a very capable detector that I have used as a loaner for beginners.
First, how many times have you read your manual? If you are fairly new to detecting reading it carefully 3 or 4 times is a must along with referring back to it regularly. The Treasure Master/TreasurePro manual is pretty short and is easy to understand.
It looks like you are on the MS Gulf coast. Does that mean you do a lot of dry sand beach and inland hunting? If so, what program mode are you hunting in:
coin and jewelry, beach or all metal? Your manual recommends that you hunt in coin and jewelry to get started which has preset discrimination of part of the iron detection range.
To your question about pinpointing and iron, depending on the size of your iron target, its depth and its condition-rusty or not, your TreasureMaster can give you a target ID number reading in coin and jewelry just about anywhere on the scale. I know you are new to this but ignore where that cursor is pointing on the detector's speedometer target scale. Many targets that you can find are not listed there and they can overlap target segments too. Pay more attention to the tones if you are using 4 tones, and to the target ID numbers. Practice at home (outside) with targets that you want to find or have found often and memorize their target ID numbers and the way they sound. Your TreasureMaster can probably give you accurate numbers in dry beach sand and sandy soil to a depth of about 5". Deeper than that, the target ID numbers and especially the target identification cursor are pretty useless. It is that way on most detectors when detecting deep targets. You have to use your ears and your experience.
So back to pinpointing. The TreasureMaster has a very good pinpointer. It can tell you fairly accurately the location, size and depth of a COIN sized object in inches. If your target happens to be larger or smaller than a US coin all bets are off. You can tell by the sound when pinpointing if it is larger than a coin sized object by the size of the response. If the sound extends over an area bigger than roughly 2" in diameter and/or if it overloads, you are probably looking at a surface target or a larger target like a big piece of an aluminum can or one (like iron, tin, a small battery or a zinc penny) that emits a large decay halo around it the longer it is buried. If it is big it could be up to a foot deep or more! So if you decide to dig and you reach the depth suggested by your pinpointer and find nothing recheck the target for size with your pinpointer or probe around in the whole and see if you hit something big deeper. Use your pinpointer for finding the exact location of your target, how deep it probably is, and how big or small it is. Don't use it mostly for trying to identify your target. If you have the concentric coil with the small open partial circle in the middle, your target should be in the center of that small circle if you have pinpointed it well and it is coin sized. Practice!!!!!
If you have changed a lot of your settings it is good to write them down and do a factory reset. Until you know your detector really well just hunt in the preset modes. I think you hold down the OPTION button while powering on the TreasureMaster and wait until you see FD on the screen and then release the option button. Try hunting in the preset modes with only some minor adjustments like the number of tones, your volume level and sensitivity. Don't run the sensitivity at max. Default should be around 5 or 6 which is plenty for most situations. Also if you set your threshold volume level above 0 you will move out of silent search and get that background hum which some people like but others don't.
The TreasureMaster likes a medium speed swing rate like 1 second to the left and 1 second to the right. No faster. Work on your swing technique so that the coil stays evenly just above the ground even at the farthest points of your swing away from you body by letting your forearm and elbow act like a hinge so that your upper arm doesn't move too much away from your body.There are plenty of good swing instruction videos on Youtube. Also, check out some of the TreasureMaster YouTube videos. Some of them are pretty informative about the TreasureMaster.
hh,
Jeff